Diarrhea in Dogs: 15 Common Causes & How To Treat It

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We dog owners pay close attention to our dog’s daily toileting activity! Consistency, volume and frequency of poop can tell us a lot about their health.

Diarrhea in dogs is not uncommon. The chances are every dog will experience it more than once throughout their lives. If you have a dog, the likelihood is that at some point you have found yourself washing away a puddle of brown liquid.

Keep reading to get clued in on the causes of the colloquial ‘runs’. We share the different types, how to help your dog feel better and when you need to worry about it.

Diarrhea in Dogs

Diarrhea in Dogs

Diarrhea is simply when there is too much liquid in the gut, causing feces to become runnier than normal.

Anything that disrupts your dog’s digestive system can result in the gut producing diarrhea. It usually happens when something disturbs the normally well-balanced digestive system of your dog.

Causes of dog diarrhea could be anything from your dog eating something they shouldn’t have to allergies and food intolerances, having a bacterial or viral disease or parasites present in the gut.

There are two main ways that diarrhea happens, not just in dogs, but in all animals:

  • Malabsorption and maldigestion
  • Intestinal hypersecretion

On a simple level it happens when there is too much water in the stool.

Malabsorption and maldigestion mean that something is preventing the gut from properly absorbing water and digesting food. This means that water that your dog drinks, and any water content of food, is not absorbed by the body. Instead it is left in the gut, coming out as runny feces.

Intestinal hypersecretion is when something is causing the cells lining the intestines to pump water into the gut. This means the water content of the gut goes up and diarrhea happens, instead of normal feces forming.

With water being lost through the gut, instead of being absorbed into the body, they can quickly become dehydrated.

The main concern with dog diarrhea is the risk of dehydration.

Diarrhea can become a vicious cycle of problems that start as a bit of an ‘icky tummy’ and become dangerous levels of completely liquid diarrhea.

Sometimes it can be the result of something making your dog feel poorly as well, meaning they might not have much energy to want to get up and drink water.

The occasional one-off runny poo certainly isn’t something to worry about in terms of your dog becoming dehydrated, especially when they still seem like their bright and cheeky self!

If diarrhea continues for longer than 48 hours, your dog might become seriously ill.

Types of Dog Diarrhea

There are different types of runny stools that your dog might experience at some point during their lives. The type of diarrhea that your dog has is a clue to what is causing it:

It is important to pay attention to exactly what your dog’s feces look like to help you understand what is going on.

There are some features that are important to take note of:

  • Consistency – stool soft or completely liquid?
  • Color – brown, yellow/green tinge, very dark (almost black), or red?
  • Frequency – how often is the diarrhea?

With an idea of exactly what your dog’s diarrhea looks like, take a look at the guide below to understand what might be causing it and how serious it is.

Loose Stool

Dog loose stool is normally when the poop is not completely liquid, but just softer.

The feces will be a bit more runny than usual.

Loose stool is just occasional, up to once a week, and the other poops will be normal consistency.

Your dog might need to pass loose stool with a bit more urgency than normal. You may find them begging to be let out in the middle of the night, or pulling for a patch of grass on a walk.

Usually, infrequent loose stools are caused by something your dog has eaten. They might have eaten something that has upset their tummy a little – too many treats, grass from the garden, or they’ve gobbled down their new chew in one go. Occasionally it can be related to a change in their normal diet.

Loose stool isn’t uncommon in dogs, considering their penchant for eating whatever they find on the floor!

If your dog has loose stools occasionally, it is nothing to worry about.

Occasionally it does become more frequent (more than once a week), looser in consistency or starts to appear bloody or dark in color. If this happens then it is time for a visit to the vet to find out what is going on.


True diarrhea is a dog pooping liquid. There will be absolutely nothing solid and they are excreting completely liquid feces. Liquid diarrhea is commonly seen when your dog has some form of infection, rather than them having eaten something they found on the floor.

Liquid poop can be a distressing experience as your dog is likely to be uncomfortable and not themselves.

If the liquid diarrhea appears to be a one-off event, then keep a close eye on your dog and give them something easy on their stomach for the next few days to give their guts a chance to recover. A gentle meal to try is plain boiled rice with plain boiled chicken.

Any poop that is completely liquid should be taken seriously.

If it happens more than once, speak to your vet about the next steps.

Diarrhea in Puppies

Diarrhea in puppies is very common. Puppy diarrhea is often caused by the stress of moving to a new home. However, it can also be the result of other things such as a change in their diet, worms or parvovirus.

Puppies are at a greater risk of dehydrating because of their small size.

If you notice your puppy has diarrhea, even with no other symptoms, call your vet and discuss what the best options are.

Bloody Diarrhea

If you notice your dog has bloody diarrhea, the first thing to do is work out what type of blood it is. Fresh blood is bright red, while partially digested blood is darker in color and can look almost black and tarry.

Once you have noted the appearance of the blood, ring your vet, and they will guide you with what to do next.

Bloody diarrhea can be caused by:

  • Parasites
  • Inflammatory disorders
  • Infections
  • Ulcers
  • Trauma to intestinal wall
  • Anal sac infections

If you see bright red blood, then check your dog’s anus for any signs of tears or irritated skin. This type of blood could mean that your dog has an injury on their bottom.

Diarrhea and Vomiting

There are a number of reasons for dog vomiting and diarrhea.

The most common reason is an infection, or that your dog has eaten something that is blocking their digestive tract.

Both infections and blocked foreign bodies need medical attention to resolve.

The risk of dehydrating is even higher if your dog is vomiting alongside having diarrhea as they are losing more fluids, so definitely contact your vet.

Why Does My Dog Have Diarrhea

There are a number of causes of diarrhea in dogs:

  • Change in their diet
  • Scavenging food
  • Food allergy
  • Parasites like hookworms
  • Infections (parvovirus, giardia or bacterial)
  • Hemorrhagic gastroenteritis
  • Colitis (inflammation of the colon)
  • Foreign body
  • Pancreatitis

It is important to get to the bottom of dog diarrhea, so that your dog can receive the right treatment and get back to their normal playful selves!

Vets can do a number of things to help diagnose the root cause of diarrhea.

As well as looking at other symptoms the dog might have, there are tests that can be done, as well as potentially using equipment like x-ray and ultrasound to help work out exactly what is causing the diarrhea.

Sudden Change In Diet

Your dog’s stomach might have become upset because of a sudden change in their diet.

This type of diarrhea happens when you change their food suddenly, instead of gradually introducing something new.

Slowly changing the kibble allows your dog’s gut to get used to the new diet and should prevent any diarrhea.

Day% of ‘old’ food% of ‘new’ food

Scavenging Food

Another reason your dog might get diarrhea is if they have eaten something they shouldn’t have. Dogs are well known for picking up all sorts of nasty things off the floor or ground while out and about. It is no surprise that sometimes these food scraps don’t agree with their tummies.

If they have just one loose stool, then give them something easy on their stomach such as plain boiled rice and chicken for the next few meals.

This should help clear up their diarrhea and make them feel better.

Food Allergies

If your dog’s diarrhea is constant but gets better when you (gradually) change their kibble, it is most likely an allergy.

Just like us humans, some dogs have food allergies and intolerances.

Allergies often manifest in dogs as itchy skin, but can also be seen as diarrhea – especially when the allergy is one of the main ingredients or proteins in their dinner.

Skin allergies are common in bully breeds like exotic bulldogs.

It can help to speak with your vet about allergy testing and allergy-friendly food.


There are several infections that can cause your dog to have diarrhea.

You may recognize the name ‘parvovirus’ as something your dog is vaccinated against in their yearly shots. The virus attacks a dog’s digestive system and causes several symptoms including vomiting, fever, loss of appetite and diarrhea.

Parvovirus is most serious in puppies under 4 months of age and quickly turns dog diarrhea into an emergency.

The best way to prevent parvovirus is to ensure your dog is fully up to date on all their shots.

There is no cure for parvo, and the only thing a vet can do is give IV fluids, antiemetics for the vomiting and antibiotics to try to prevent secondary infections.

Another type of infection that causes diarrhea is bacterial infections.

If a bacterial infection is causing diarrhea, you will likely also see vomiting, fever, lethargy, loss of appetite, and your dog being generally unwell and not themselves.

Bacterial infections need antibiotic treatment and your dog might also need IV fluids to resolve or prevent any dehydration.

The two most common bacterial food-poisoning culprits are salmonella and campylobacter.


There are several parasites that cause diarrhea in dogs.

Parasites damage the lining of your dog’s gut, which means they cannot properly absorb water or digest food.

The first of these parasites is called giardia. Your dog must ingest giardia for them to get infected with it, but giardia is pretty common, so it is easy for your dog to pick it up while out on walks.

Giardia infections also cause weight loss, vomiting and a poor coat condition.

There is no prevention for giardia, however if diagnosed early it can be cured.

Some parasites can be easily prevented. They are known as ‘worms’ and there are three types in the US: whipworm, hookworm and roundworm.

All three cause damage to gut lining and infection results in diarrhea.

Worms are easily prevented by giving your dog preventative worming medication every 3 months, or more often if your dog particularly loves to scavenge and eat things they shouldn’t!

Other common symptoms of worms are “scooting”, where your dog scratches their bottom along the floor, weight loss, vomiting, and bloating (especially in puppies).


Some causes of diarrhea that don’t fit into a category include:

  • Hemorrhagic gastroenteritis
  • Stuck foreign body
  • Colitis

Hemorrhagic gastroenteritis is a life-threatening condition with severe vomiting and a sudden onset of liquid, bloody diarrhea. Your dog will likely be feeling very poorly, be very lethargic, have a fever, and be showing signs of abdominal pain.

It is important that you take them straight to the vet.

Foreign bodies are when there is something in your dog’s digestive system that shouldn’t be there – often stolen socks, destroyed squeaky toys, or even sticks and stones!

A foreign body can cause a blockage in your dog’s digestive system. You will often see vomiting as well as diarrhea, and your dog might have abdominal pain. If you suspect your dog has eaten something that might block their digestive tract, you should take them straight to the vet.

Colitis is inflammation of the large intestines and is not as much of an emergency as hemorrhagic gastroenteritis or a foreign body.

The classic sign of colitis is soft diarrhea, not liquid. The soft poop often contains fresh blood and mucus. Colitis can be caused by parasites, infections, or allergies.

Pancreatitis is another inflammation, like colitis, that results in diarrhea. It involves inflammation of the pancreas, and you will also see vomiting, which is typically green in color and contains bile.

What Can I Give My Dog For Diarrhea?

Dog Diarrhea

A bland diet is the best way to treat diarrhea in dogs at home.

Bland food will help settle their digestive system and give it a chance to recover and get back to normal.

Feeding plain food with no salt, pepper, or spices is one of the best things you can give a dog for diarrhea:

  • Plain boiled chicken or turkey
  • Plain boiled white rice
  • Scrambled egg (plain with no milk or butter)
  • Plain baked sweet potato

In addition to feeding a bland diet, you can give your dog probiotics such as Pro-Kolin. Probiotics top up the guts natural ‘good bacteria’ which might need a helping hand to fight any nasty ones making your dog sick.

Feeding small, bland meals throughout the day will help to stop dog diarrhea. It will prevent their digestive system getting overwhelmed and gives it time to process the last meal before starting again.

Plain, bland diets should only be given for 3 days at most. This is because they don’t provide your dog with all the essential vitamins and minerals they normally get from dog food.

If this home remedy hasn’t worked after 3 days, you should consult a vet.

When Should You Be Concerned

There are some situations where diarrhea is considered more of an emergency:

  • Puppies or elderly dogs.
  • Diabetic dogs.
  • Dogs with symptoms other than diarrhea, such as vomiting or a fever.
  • A dog not responding to a bland diet and probiotics at home after 48 hours.

If your dog’s diarrhea has been ongoing for less than a day, and they don’t fall into any of the emergency categories above, try feeding a bland diet and see if it will resolve itself.

The main concern with diarrhea continuing for longer than 48 hours is the risk of dehydration.

Try to make sure you are encouraging your dog to drink more and monitor their fluid intake to make sure they are getting plenty of water.

If the diarrhea is improving within 48 hours on a bland diet, they are drinking plenty of water and are acting fine, then continue to monitor them for another few days at home.

However, if your dog has had diarrhea for 5 days and they still aren’t showing any signs of getting better, it is worth contacting the vets. Your dog might have something more complicated that a bland diet and probiotics can’t treat.

Quick Overview

Diarrhea is when there is too much liquid in the gut, resulting in runny and loose stool.

If your dog has diarrhea, take note of the consistency, color and frequency. This will help to give you clues as to what exactly is going on.

There are a number of different causes of diarrhea which can include:

  • Change in their diet
  • Scavenging food
  • Food allergy
  • Parasites like hookworms
  • Infections (parvovirus, giardia or bacterial)
  • Pyometra (females)

The number one concern with diarrhea is the potential for your dog to become dehydrated as a result of the loss of fluids.

Diarrhea can be treated at home by giving a bland diet, such as chicken and rice, for up to 48 hours. After this, dehydration becomes a worry and you should contact your vet.

If your dog has symptoms such as vomiting or fever, or is a puppy or an elderly dog, you should contact your vet immediately.

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